I´m very sorry for posting the pictures of the gunarrow so late! The quality of the pictures is not as good as I wished. I actually wanted to take some pictures of the gunarrow again, but I´m afraid to say that the wallarmbrust and the gun arrow were not on exhibit anymore when I was there last time. The museum has been closed for a few months and big parts of the display have changed - mostely but not completely in a good way...
Later I somehow forgot about your request.

So here are the pictures of the gunarrow. I will also attach some other pictures of other crossbowbolts and some detailed pictures of the prod of the wallarmbrust.